Sendio 1.0.0

send.io .NET SDK

The official .NET library for the send.io email API. Targets .NET 8 and .NET 10 (apps on .NET 9 use the .NET 8 build).

Full API reference: https://developer.send.io/docs/api

Install

dotnet add package Sendio

Optional companion packages:

• Sendio.Webhooks: ASP.NET helpers to receive and verify send.io webhook events
• Sendio.FluentEmail: a FluentEmail sender

Quick start

Create an API key in the send.io dashboard (keys start with mx_).

Without dependency injection:

using Sendio;

ISendio sendio = SendioClient.Create( "mx_123" );   // or SendioClient.Create() to read SENDIO_API_KEY

var resp = await sendio.EmailSendAsync( new EmailMessage()
{
    From = "Acme <onboarding@yourdomain.com>",
    To = "delivered@send.io",
    Subject = "Hello from .NET",
    HtmlBody = "<strong>It works!</strong>",
} );

Console.WriteLine( resp.Content );   // email id

With dependency injection (ASP.NET Core and generic host):

using Sendio;

builder.Services.AddSendio( o =>
{
    o.ApiToken = builder.Configuration["Sendio:ApiKey"]!;   // omit to use SENDIO_API_KEY
} );

// or simply:
builder.Services.AddSendio( "mx_123" );

Then inject ISendio:

public class Signup( ISendio sendio )
{
    public Task Welcome( string to ) => sendio.EmailSendAsync( new EmailMessage()
    {
        From = "Acme <onboarding@yourdomain.com>",
        To = to,
        Subject = "Welcome",
        TextBody = "Thanks for signing up!",
    } );
}

Send a batch

Up to 100 emails in one request:

var resp = await sendio.EmailBatchAsync( new[]
{
    new EmailMessage() { From = "Acme <onboarding@yourdomain.com>", To = "delivered@send.io", Subject = "First",  TextBody = "one" },
    new EmailMessage() { From = "Acme <onboarding@yourdomain.com>", To = "delivered@send.io", Subject = "Second", TextBody = "two" },
} );

foreach ( var id in resp.Content )
    Console.WriteLine( id );

Retrieve an email

var email = await sendio.EmailRetrieveAsync( emailId );

Console.WriteLine( $"{email.Content.Subject} {email.Content.LastEvent}" );

Domains

var added = await sendio.DomainAddAsync( "yourdomain.com" );
await sendio.DomainVerifyAsync( added.Content.Id );

var domains = await sendio.DomainListAsync();

foreach ( var d in domains.Content )
    Console.WriteLine( $"{d.Name} {d.Status}" );

Mailboxes

Mailboxes are real email accounts with an IMAP/SMTP login. The login is only returned on creation (when IMAP/SMTP is ready) and on a password reset; the password is also an API key for that mailbox.

// The domain must be verified.
var mailbox = await sendio.MailboxCreateAsync( new MailboxData() { Address = "sales@yourdomain.com" } );

if ( mailbox.Content.Credentials != null )
    Console.WriteLine( $"{mailbox.Content.Credentials.Smtp.Host} {mailbox.Content.Credentials.Password}" );

await sendio.MailboxUpdateAsync( mailbox.Content.Id, new MailboxUpdateData() { WarmupEnabled = false } );

// The old password stops working.
var reset = await sendio.MailboxResetPasswordAsync( mailbox.Content.Id );

var mailboxes = await sendio.MailboxListAsync();

foreach ( var m in mailboxes.Content )
    Console.WriteLine( $"{m.Address} {m.Health}" );

// Removes the email account, and the agent inbox on it, if any.
await sendio.MailboxDeleteAsync( mailbox.Content.Id );

ISendio also covers emails (schedule, cancel, list, attachments), receiving (inbound), API keys, audiences, contacts, contact properties, segments, topics, broadcasts, templates, webhooks, events, automations, suppressions, logs, metrics and usage.

Configuration

Values set in code win over the environment. To point at another environment (for example a local test server):

var sendio = SendioClient.Create( new SendioClientOptions()
{
    ApiToken = "mx_123",
    ApiUrl = "http://localhost:8080",
} );

Every request carries the User-Agent: sendio-dotnet:<version> header.

Error handling

By default a failed call throws SendioException, which carries the HTTP status code, the API error type and the rate limit headers:

try
{
    await sendio.EmailSendAsync( message );
}
catch ( SendioException ex )
{
    Console.WriteLine( $"{ex.StatusCode} {ex.ErrorType}: {ex.Message}" );
}

Set ThrowExceptions = false in SendioClientOptions to get a SendioResponse with Success == false and an Exception property instead.

License

MIT. See LICENSE and NOTICE.